Ukrainian government forces have reclaimed the port city of Mariupol after heavy fighting with pro-Russian separatists.

The Interior Ministry said troops stormed rebel-held buildings after they were surrounded and those inside given 10 minutes to surrender.

At least five separatists and two Ukrainian soldiers were killed in the gun battle, before the rebels fled the city.

Government forces also regained control of a 75-mile stretch of the border with Russia.

Interior Minister Arsen Avakov wrote on Facebook "At 10:34am the Ukrainian flag was raised over City Hall in Mariupol".

He added that National Guard and Interior Ministry units took part in the battle alongside special forces.

Mariupol lies on major roads from the south-eastern border of Ukraine.

The separatists seized control of government buildings across eastern Ukraine after Russia annexed Crimea in March following the overthrow of former president Viktor Yanukovych.

The new President, Petro Poroshenko, has stepped up the military operation against the rebels since his election on May 25th.

Relations between Ukraine and Russia, already strained by the occupation of Crimea, have remained hostile after Ukraine accused its neighbour of supporting rebels and allowing them to bring equipment over the border.

Talks between the two countries on a gas pricing row have also stalled.